UC Berkeley

In the year 2016, it is estimated that 282,000 people were living with a spinal cord injury (SCI) in the United States. Furthermore, it is estimated that 17,000 new SCI cases arise each year in the United States. As a result of their injuries, those affected by SCIs are commonly subjected to a plethora of physical, psychological, and financial hardships. These hardships can be so severe that, on average, individuals affected by SCIs experience significantly lower life expectancies than those without SCIs. In an attempt to improve the quality and span of life of individuals with SCIs, there has been an increased interest in pursuing technologies such as the exoskeleton - a wearable robotic device which provides support and bipedal locomotion for individuals with mobility disorders. Despite the promise of exoskeletons, there are still clear technical inadequacies that exist in the field itself. One of the most glaring inadequacies pertains to user safety and the prevention of falls while wearing an exoskeleton.

To maintain stability, an exoskeleton user will almost always walk with the assistance of crutches. While the use of crutches clearly provides some degree of stability, crutch usage inherently places substantial responsibility on the exoskeleton user to manipulate said crutches correctly. With one small misplacement of the crutches as the prerequisite for an adverse event, even the most experienced exoskeleton users run a high risk of falling at all times. Thus, in the opinion of the author, crutches are not an acceptable solution for stable exoskeleton locomotion.

In this thesis, the primary objective is to provide locomotion in an exoskeleton with a reduced chance of falling (compared to locomotion in an exoskeleton with crutches). To satisfy said objective, an exoskeleton support mechanism (ESM) is proposed by the author. This thesis provides a thorough explanation of the background theory, system architecture, and design analysis that went into making the ESM a reality. Additionally, through a combination of experimentation and anecdotal findings (described within), use of the ESM in combination with a walker is shown to provide locomotion in an exoskeleton with a reduced chance of falling - thereby satisfying the primary objective. The exoskeleton support mechanism presented in this thesis clearly advances the state of the art in medical exoskeleton stabilization while also acting as a critical puzzle piece in providing a better quality of life for those affected by spinal cord injuries.